On of the most unique geologic features of Catalina is the deposits of steatite, or soapstone, that was such an important trade item in prehistory. It is the only in the Channel where steatite is found, and gave the islanders a very valuable trade item as it was the primary materials for the native bowls, pipes, effigies and other carved implements.

Like most of the other islands, Catalina has areas of volcanic igneous rock formation, and well as sedimentary formation of ocean floor lifted by seismic forces, and metamorphic rock that has undergone geologic pressures to transform its sandstone base into more durable stone deposits. The metamorphic rock is the oldest, dating back to over 150 million years old. Next oldest is the igneous rock that was brought to the surface during volcanic activities. And the sandstone is the youngest geologic formation.

The highest mountain on Catalina are Mt. Orizaba at 2069 feet, and Mt. Black Jack - site of a silver mine in the 1920s - at 2006 feet. The overall land mass of Catalina is 75 square miles, the third largest of the California Channel Islands.

Mining has also played a more prominent role in Catalina Island development than any of the other islands. Before the Gold Rush began following the Northern California gold discovery in 1848, there were rumors that gold had been discovered on Catalina, and there was a discovery on the mainland in the San Fernando area that pre-dates the gold rush.

As the gold fields in the north came under prized ownership, enterprising individuals began to search for gold elsewhere. Catalina was one location where miners came to search for their fortune. There was a discovery of gold on the island, as well as silver. A mine was opened on Catalina in 1860 by Santos Louis Bouhchette, and operated until 1874, extracting gold, silver and lead from the canyons of northern Catalina. It was called the mineral Hills Mine, and although it promised a gold boom for Catalina, it did not prove financially successful. But there was not enough quantity to warrant a large-scale mining operation.

In the mid 1920s, mining activity began again on Catalina, this time at the Renton Mine in the mountains behind Pebbly beach at a mine on Mount Black Jack. These mines pulled ore out of the mountains that was processed at the Silver Isle 100 ton Flotation Mill to extract silver, zinc, and lead. The operation closed after two years as it failed to be as profitable as expected.